Lightning or surge arrester



July' 3, 1928.

L. C. GRANT LIGHTNING 0R SURGE ARRESTER Filed Oct. 1925 I W I I I I I I I [III/II IIIIIIIIA llI/IIIIIIIIIIIflI/II I I z Patented July 3, 1928..

UNITED STATES 1,675,649 PATENT OFFICE.

LEWIS COLIN GRANT, N EWCASTLE-UPON-TYNE, ENGLAND, ASSIGNOR 1'0 ELECTRI- GAL IMPROVEMENTS LIMITED, 0]? NEWCASTLE-UPON-TYNE, ENGLAND, A COI- PANY OF GREAT BRITAIN.

LIGHTNING OiB. SURGE ARRESTER.

Application flled October 5, 1925. Serial No. 60,592.

This invention relates to lightning or surge arresters and has particular reference to arresters intended primarily to deal with traveling and standing waves of high frequency on electric transmission lines such as Waves caused by lightn'n or surges which may be due to an induce; line charge, an arcing fault or any phenomena usually classed as lightning and transient line sur es. c

any arresters have been proposed for this purpose and in general, they have been intended to remove the charge from-the lineby a discharge toearth. V

The primary object of the present invention is to provide a simple and reliable arrester which will dissipate the energy due to a surge without having to earth the line, and for this purpose the arrester is so arranged that the energy of a surge is transmitted electromagnetically from a primary connected in series with or formin part of the line to a secondary whence it s dissipated in the form of heat.

A further object of the invention is to.

the accompanying drawings and from theap ended claims.

he accompanying drawings show one practical construction of arrester according to the invention. In these drawings,

Figure 1 is a'longi-tudinal section, a part being broken away,

Figure 2 shows on a smaller scale an external view of the arrester shown in Figure 1 provided with insulated terminals for connection to the line.

In the construction of Figure 1 the primary A of the transformer constituting the arrester is composed of four conductors A A A A of squareasection copper connected in parallel with one another. These ,conductors are wound one upon the other with consecutive turns of each winding close together so that the whole primary is in the form of a compacttubular structure. The

four windings are arran ed to cross over,

one another near the mid e of the primary (as indicated at B), the outer windmg on windings.

I transferre one side becoming the inner winding on the other side and so on. This arrangement enables the resistances and impedances of the four windings to be made equal to one another. Heavy paper insulation C (for example, capable of withstanding 40,000 volts) is provided between the superimposed windings and between adjacent turns of the The secondary consists of two tubes E, F disposed respectively around and within the primary A, the two tubes being electrically connected together by end plates E Tubular paper insulation D arranged in one or more layers is provided to insulate the primaryA from the tubes E, F and the end plates E, this insulation being passed throu at D to allow of of the primary.

The arrangement is such that there is a very close coupling between rimary and secondary with adequate ins ation, whilst the whole structure is mechanically very strong and considerable resistance is offered against circumferential expansion of the primary.

"The energy of a surge in the line (to which the rimary is connected in series) is (i electromagneticall from the the external connection rima A to the secondary tubes E and which actsto convert this ener into the form of heat and to eat by h holes in the end plates (as shownstructed of a material which has h'tgh specific heat, high thermal conductivi high melting point and comparatively high ohmic resistance. Cast iron and other forms of iron comply to a large extent with these conditions, and a very suitable material is a recently developed form of iron which has an extremely high specific resistance (of the order of 140 micro-ohms per n imetre cube) and has also the furt er important advantage of being substantially non-magnetic.

' The tube E forms the outer casing of the arrester and is provided with flanges E to receive end plates E (see Figure 2) which carry insulated terminals E by means of which the primary is connected in series ployed for the connection of the arrester to the line or apparatus to be protected.

Owing to the fact that the secondary is high aperiodic, it is possible'to abstract so much energy from the surge that the building-up of potential is prevented and no disruptive discharge takes place. Under normal working conditions, as the line frequency is relatively very low, the amount of energy transferred to the secondary is negligible,

What I claim as my invention and desire to secure by Letters Patent is-:--

1. A lightning or surge arrester in the form of a transformer comprising a secondary which consists of two concentric tubes electrically connected together, anda primary winding disposed in the annular space between the two tubes, the secondary acting to dissipate in the form of heat energy which it derives from a surge in the primary.

2. A lightning or surge arrester comprising an inductive -winding,which is formed of a group of conductors connected in parallel with one another and in series with the line and which constitutes the primary of a transformer, and a secondary part of which surrounds the primary whilst part is disposed within the primary, such secondary acting to dissipatein the'form of heat energy which it derives from a surge in p the primary.

8. A lightning ary which consists of two concentric tubes or surge arrester in the form of a transtormer comprising a secondry winding disposed in the annular space between the two tubes and formed of insulated square-section .conductor, the second aryacting to dissipate in the form of heat energy which it derives from a surge in the primary.

5. A lightning or surge arrester in the form of a transformer comprising a secondary which consists of two concentric tubes electrically connected together, a primary which consists of a group of superimposed other each winding being formed of insulated square-section conductor with its adjacent turns wound closely together so that the whole primary is in the form of a compact tubular structure disposed within the annular space between the two tubes, and two tubular insulating layers disposed respectively betweenthe primary and the two tubes, the secondary acting todissipate in the .form of heat energy which it derives from a surge in the primary.

In testimony whereof I have signed my name to this specification.

r LEWIS COLIN GRANT.

I windings connected in parallel with one an- I 

